Question

If I use register names I get:

Error: illegal operands `add $t0,$zero,$zero' 

If I use register number ($8 instead of $t0 and $0 instead of $zero) it works. (I’m using binutils 2.17).

Answer 1

The GNU assembler doesn’t support symbolic register names directly. A common approach, if using gcc to drive the assembler, is to use the ‘.S’ extension for the assembler source file (which tells gcc to pass the source through the C preprocessor before the assembler) and #include a header file containing definitions like:

#define zero $0 #define v0   $2 #define v1   $3 

Then the assembler source can have statements like

add v0, zero, zero